Power operating mechanism for typewriting machines



Nov 9, 194.8.

R. VON REPPERT POWER OPERATING MECHANISM FOR TYPEWRITING MACHINES Filed Oct. 7, 1944 INVENTOR ffi @ORNEY Patented Nov. 9, 1948 POWER OPERATING MECHANISM FOR TYPEWRITING MACHINES Richard -von.Reppcrt, Rochester, N. Y., assignor .to international Business Machines :Corporavtion, New York, N. Y... a corporation of New York Application-October '7, 1944, Serial No. 557,635

3 Claims.

This invention relates to .typwriting machines.

The principal object of the present invention is to provide an improved power operating mechanism for a poweroperated typewriter.

An object is to provide a power operating mechanism which .is capable of actuating the mechanisms of a poweroperated typewriter machine more smoothly and more positively.

An object is to provide an improved cam .unit for power "mechanism of .the type used in the well-known Electromatic typewriter in which cam unitscooperate with a power roller under control-of'the keys of the typewriter.

An object is to provide a cam unit which is capable of delivering power-more smoothly and more advantageously than :heretofore was possible.

An object is to provide an improved cairn unit of the single lobe type.

An object is to provide a cam unit which is.

especially suitable for operating those mechanisms of a typewriter which require considerably more power to operate thanthe-type bars.

An object is to provide a cam unit which is capable of operating the shift mechanism of a typewriter -more smoothly and more positively than heretofore.

Other objects-of the invention will be pointed out in the following description and claim and illustrated in the accompanying drawings'which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. l is a vertical section showing a key controlled cam unit incorporating the present invention and the shift mechanism of .a typewriting machine, the cam unit being shown in the normal or unoperated position.

Fig. 2 is a view showing the cam unit in a partly operated position. I

Fig. 3 is a large scale view showing the cam and'its detent means.

- For convenience in illustrating the invention it is'shown in-the drawings as operating :the shift mechanism of the well-known Electromatic power operated typewriter. However, it will be understood that the invention is equally applicable not only to other machines and shift mechanisms but also may be usedto operate'other devices of a typewriter. The shift mechanism shown inthe drawings is similar to the one disclosed in Patent .No. 1 9115 ;097. portion of the ;;type basket .frametis desig nated; HI .;in,;;Fig. -.1.- This aframe ismounted on two pins 21a and 2|:b.

four leaf springs I of which'on'ly. two' are shown in Fig. .1, there being 1a vpairof these springs at eachsid'e of the type basket. These springs are secured s'to'fixed parts of the main framework t2 and act as parallel :motion links to cause the type 'baskettomove in substantially a straight line for the relatively short distance the basket I'IHUSIZ 1 move downwardly. :from the lowercase vposition rofv Fig. lxto'the upper case position. .The type basketiframeuis provided with a stop screw IE3, which passes lthroughiaholein arpost'or-xstrap 1M secured to a part of the-"mainsframework, and

.is threaded into a portion of the type :basket. The screw I3 alsovhas an adjustable stop collar 5'5 threaded thereon "which :limits downward movement of the type basket to the-topper case cposition. .There is a stop screw 13 and a cooperating post M .Onr'fifiJChSideOf the type basket.

Adjustabiy secured :to the type basket iii are two arms like I16, one on each side .of the type Ibasket, which are connected-by links'lr'l to :arms I8 secured to a cross shaft I9 suitably .ai'ourna'led in the main framework. .On'e ofzthe arms 18 is connected by a link 2!] to a lever 2| which is pivoted at 22 to ethe'fram'ework of the machine. The lever?! has attached :to it a'plate 23 which is spaced from the lever .2! and mounted on Between the plate 23 and the lever 21 is a T-link 24 'which is pivoted at 25a to a three-armed lever 2-5. This :lever 25 is pivoted at-26 ona fixed part-of the framework. The lever 25 is heldlin the position of Fig. 1 by a spring "21 anchored to one of the arms of .the lever and holding this same arm against a stop screw 2-8 carried by the 'main framework.

The third arm of the :lever 25 is connected by a link ".28 to the cam= unit 29 which comprises the present invention. Cooperating with the lever -2| is a pair-of toggle springs. 30 which are interposed between pins carried by the main framework and pins on the lever 21. These etoggle springs act to hold the lever 2| in either of two positions, one of which, the lowercase position, is shown inFig. 1. The T-link 24 has a-pin and slot connection at 24a to .thercaseshift key 3| which is pivoted on a fulcrum rod '32 serving as "the pivot for the keys of the keyboard. An extension 3l=a of the key 31 has the pin and slot connection 24a to the T-link '24.

The'cam unit 29.;is pivotedon 1a fulcrum rod .33 on which also are "pivoted other cam units which operate the type bars of the machine, in cooperation with the usualpower roller 34 which :rotites .in :the a direction of the arrow while the machine is in use. Thescam unit comprises' 'a 3 pair of plates 29a spaced apart between which is pivoted at 35 the circular cam 36, the pivot 35 being eccentric with respect to the center of the cam 36. Pivoted at 291) between the plates 29a comprising the cam unit frame and behind the circular cam 36, is an arm 31' which is urged in a clockwise direction by a torsion spring 38 attached to the cam frame and the arm 31respectively. The arm 31 engages a boss or stud 36a normally located below and to the right of the pivot 35 of the cam 36 whereby the arm 31 tends to rotate the cam 39 clockwise from the position of Fig. 1.

Rotation of the cam 36 normally is prevented by a lug formed on a pin 36b carried by the cam 36 and most clearly shown in Fig. 2 by reason of engagement of this lug with 2. lug 39a formed in a detent lever 39 which is also pivoted at 2% in the cam frame. In the positions of the parts in Fig. 1, the cam 36 is held just clear of the power roller 34. The lever 39 has a pin and slot connection at 39b with an extension 3117 of the shift key 3|, this extension 3H) in Fig. 1 holding the detent lever 39 with its lug 39a in the path of the lug 36b.

Pivoted at 390 on the detent lever 39 is a three-armed dog ll] one arm of which is connected to a spring 4| anchored to a lug or ear formed in the lever 39 and tending to rock the dog 40 clockwise. One of the arms of the dog 40 has a bent over lug 40a which cooperates with the edge of lever 39 to limit counterclockwise rotation of the dog. A third arm of the dog 40 is formed with a bent over lug 40b of sufficient length to engage the lug on pin 36b under certain conditions. The front plate 29a of the cam frame is formed with a notch or shoulder 29c which may be engaged by the lug 402) under certain conditions. The cam frame also is formed with a lug 29d which is bent to extend alongside of the lever 39 and act as a guide for said lever.

The operation of these parts will now be described.

Under normal conditions the lug on pin 36b engages the lug 39a of detent lever 39 and prevents clockwise rotation of the cam 36 thus rendering the cam unit inoperative by the power roller. When the shift key 3| is depressed the detent lever 39 is rocked to the position of Fig. 2. This removes the lug 39a from the path of the lug on pin 36b and permits the spring arm 3! initially to rotate the cam 36 clockwise far enough for the periphery of the cam to engage the power roller 34 and be rotated thereby. It should be mentioned at this point that the lug 49?), when the parts are in the positions of Fig. 1, is located a little above the lug 39a whereby the aforesaid movement of the lever 99 moves the lug 40b in a path which passes above the lug 361) so that the latter does not interfere with the movement of the lever 39. Lug 49b stops in the path "of the lug on pin 35b and also moves upwardly into a notch 290 in the cam frame plate 29a.

On account of the circular configuration of' the cam unit 29, the cam frame 29a will berocked counterclockwise slowly at first but with increased velocity until the cam 36 has turned one quarter of a revolution after which the velocity will diminish until the high point of the draws down the link 28 thereby rocking the lever 25 in a-olockwise direction.

In effecting a shift operation it is necessary to either hold the shift key 3! down with a finger or lock it down with the usual shift lock key. The initial depression of the key 3l lifts the extension 31a and rocks the T-link 24 clockwise to bring the upper lug Z lblnto a position on a level with pin 2Ia before lug] 39a clears the lug on pin 36b. Consequently the subsequent rocking of the cam unit 29 in a counterclockwise direction to rock the lever 25 clockwise will cause the T-link 24 to be drawn to the right by lever 25, thereby rocking lever 2| in a clockwise direction. This rocks the shaft l9 counterclockwise, drawing down the links I1, and shifting the type basket I 9 downwardly to the upper case position. The cam 36 now is rotated by the power roller slightly more than a half revolution to the position of Fig. 2.

At the end of the first full revolution of the cam 36 the lug on pin 36b will engage the lug 49b and rock the dog 40 counterclockwise to the position of Fig. 2 thereby arresting the rotation of the cam unit inthe position of Fig. 2 in which position it remains as long as the key is held depressed.

With the key held down and the type basket shifted, the operator now proceeds to type the desired character or characters in the upper case.

Release of the key 3| allows the lever 39 to swing back to the position of Fig. 1, again releasing the lug on pin 3%, and permits another revolution of the cam 36 at the end of which the lug 35b will reengage the lug 39a as in Fig. 1. The notch 29a in cooperation with lug 4901. causes the lever 39 to be locked in the position of Fig. 2 while the cam 36 isturning through the first revolution and serves to hold the key depressed during this period.

When the shift key 31 is released after the first revolution of the cam 36 of the cam unit, the T-link 24 will be allowed to drop thereby placing the lug 24c directly in horizontal alignment with the pin 24b whereby the second revolution of the cam rocks the lever 21 counterclockwise to restore the type basket Ill to lower case position. Theslot of the pin and slot connection 391) is located in the extension 311) and the pin is carried by the lever 39. The slot is so disposed that the rocking of the cam unit 29 does not disturb the relation between the lever 39 and the cam frame 290 determined by the status of the key.

One of the advantages of the cam unit described above is that the initial rocking movements of the cam unit are effected with slow acceleration and deceleration whereby the type basket is started in motion and stopped substantially without shock thereby greatly reducing the noise of the shift operation. This arises from the shape of the cam 36 and the fact that the cam is normally in a dead center eccentric position with respect to the axis of the power roller. Furthermore the initial force to shift the type basket one. waylor another is great because of the favorable-force angles arising from the shape of the caml'f This makes it possible for the power roller to start the cam in rotation almost instantly since arelatively small rotational force applied to the cam produces a much larger force to swing the cam unit;

Another advantage is that the restoring of parts connected to the cam unit during the second half of each'revolution of the cam, during which the T-link '24 is moved to the left, is. eff'ected more smoothly since the cam during-this part of its operation rolls over the power roller and allows the cam frame to restore only as fast as permitted by the eccentric shape of the cam. This results in quieting the action of the parts directly connected to the cam unit and makes the cam unit quieter its restoring motion.

A further advantage of the cam unit consists in the provision of the locking notch 290 which makes the cam especially suitable for applications other than the actuation of a shift mechanism. It will be noted that, if key 31 is momentarily depressed and released by the operator. the dog 40 will lock the key down by reason of the lug 40b entering the notch 290. Under these conditions, the cam 36 will make a full revolution at the end of which the lug on the pin 3% will engage the lug 40b and move it clear of the notch 290. This will allow the detent lever 39 to swing clockwise and carry the lug 39a into the path of the lug on pin 36b, thereby stopping the cam 36 in the position of Fig. 1 and permitting the key to restore.

It is thus possible to use the cam unit where it might be desired to have a single operation of a connected part or device with a momentary depression of the key or two operations with a sustained depression of the key. For example, it is generally customary to space twice after the period ending a sentence and only space once between words. Thus the cam unit disclosed herein could be used to effect a saving of time and effort by coupling it to the usual space mechanism for control by the space bar. With a momentary depression of the space bar the carriage would be spaced once, whereas, with a slightly sustained depression of the space bar, the carriage would be spaced twice. The mechanism could also be used for actuating a line space mechanism to single space indented and quoted matter and to double space normal context.

While there have been shown and described and pointed out the fundamental novel features of the invention, as applied to a single illustrative embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is the intention therefore to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a power operating mechanism for typewriting machines, a power roller, a function controlling key, and a cam unit cooperating with said roller, said cam unit including a cam rotatable by the power roller to perform the function controlled by said key, said cam unit including a first detent normally restraining the cam unit against rotation by the power roller and being releasable by said key to permit rotation of the cam by said roller, said cam unit including a second detent having a portion thereof engaged by a part of said cam at the end of its rotation by the power roller and movable by the cam to arrest the cam in a position beyond the position in which the cam is held by the first detent, said second detent being moved into operative position by said key when the first detent is released and, upon release of the key after a sustained op eration thereof, moving out of engagement with said part of said cam to permit a second rotation of the cam by said power roller.

2. In a power operating mechanism for typewriting machines, a power roller, a function controlling key, and a cam unit cooperating with said roller, said cam unit including a cam rotatable by the power roller to perform the function controlled by said key, said cam unit including a first detent normally restraining the cam unit against rotation by the power roller and being releasable by said key to permit rotation of the cam by said roller, said cam unit including a second detent movably mounted on the first detent and having a portion engaged by a part of said cam at the end of its rotation by the power roller, said second detent being movable by the cam to arrest the cam in a position beyond the position in which the cam is held by the first detent. said second detent being moved into operative position by the first detent when the first detent is released by said key and, upon release of the key after a sustained operation thereof, moving said portion out of engagement with said part or" said cam to permit a second rotation of the cam by said power roller.

3. In a power operating mechanism for typewriting machines, a power roller, a function controlling key, and a cam unit cooperating with said power roller, said cam unit including a cam rotatable by the power roller to perform the function controlled by said key, said cam unit including a first detent normally restraining the cam against rotation by the power roller and being releasable by said key to permit rotation of the cam by said roller, said cam unit including a second detent for holding said first detent in released position and also operative to hold the key in operated position when the key is momentarily operated, said second detent having a portion thereof coacting with a part of said cam, when the first detent is held in released position, to effect release of the second detent and key and at the same time render said first detent effective to limit rotation of the cam to a single revolution, said second detent yielding when engaged by said part of said cam while the key is held in operated position long enough to permit said cam to rotate beyond the control of said first detent to permit said cam to rotate a second time and effect a second operation of said cam unit upon release of said key.

RICHARD VON REPPERT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,688,380 Dorsey Oct. 23, 1928 1,777,055 Thompson Sept. 30, 1930 1,924,140 Von Reppert Aug. 29, 1933 1,945,097 Thompson Jan. 30, 1934 2,188.935 Wittenmyer Feb. 6, 1940 2,223,235 Thompson Nov. 26, 1940 

